Ammonia fuel sealing double-wall pipe ventilation system

Abstract

The invention discloses an ammonia fuel sealing double-wall pipe ventilation system. The device comprises a first double-wall pipe, a second double-wall pipe, a ventilation box and an ejector ventilation system, the ejector ventilation system comprises an ejector water pump, an ejector and an ejector driving water tank, the first double-wall pipe and a first ammonia supply pipe in the first double-wall pipe form a first annular space, and the first annular space is connected with a ventilation inlet through a first ventilation pipeline; a ventilation box connected with a compressed air system is arranged on the first ventilation pipeline, and the first ventilation pipeline is respectively connected with a nitrogen supply system and an ammonia treatment and recovery system; the second double-wall pipe and the outer wall of a second ammonia supply pipe in the second double-wall pipe form a second annular space, the second double-wall pipe is connected with a ventilation outlet, an ammonia treatment and recovery system and a nitrogen supply system through a second ventilation pipeline, an ejector ventilation system is arranged on the second ventilation pipeline, and the first annular space and the second annular space are communicated in the main machine. And a plurality of sensors are arranged in the host. The system is high in reliability, ammonia leakage is avoided, and effective emission of ammonia steam is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shipbuilding, in particular to an ammonia fuel sealed double-wall pipe ventilation system. BACKGROUND

[0002] As a clean fuel, ammonia is zero-carbon, sulfur-free and toxic. Now, major marine main engine companies are independently developing ammonia power main engines. Ammonia passes through a low-pressure pump, a filter, a heat exchanger, a high-pressure pump, and a fuel supply valve group to the main engine. The fuel supply valve group is arranged in the fuel supply room, which is a gas safety cabin. The fuel supply pipe must be a double-wall pipe in the cabin, the inner pipe is an ammonia supply pipe, and the annular space between the outer pipe and the inner pipe is a ventilation system. The inlet is compressed air, and the outlet is an ammonia adsorption device. When the inner pipe leaks, the ammonia vapor in the double-wall pipe annular space is blown to the ammonia adsorption device by the fan.

[0003] At present, the fan used for ammonia vapor purging is an electrically driven fan. Since the shaft seal of the centrifugal fan cannot be completely sealed, in order to prevent the leaked ammonia from leaking again through the fan itself, considering the possible leakage of the fan itself, an additional toxic area is caused. Therefore, it is urgent to propose an ammonia fuel sealed double-wall pipe ventilation system that is relatively reliable and can effectively prevent ammonia leakage, and effectively discharge ammonia vapor. SUMMARY

[0004] To solve the above technical problems, the present application provides an ammonia fuel sealed double-wall pipe ventilation system, which effectively avoids the danger caused by fan leakage and is suitable for all types of ammonia fuel power ships, with broad market prospects.

[0005] The technical solution adopted by the present application is: An ammonia fuel sealed double-wall pipe ventilation system, comprising a first double-wall pipe, a second double-wall pipe, a ventilation box, and an ejector ventilation system. A first ammonia supply pipe is arranged in the first double-wall pipe, one end of the first ammonia supply pipe is connected with an ammonia fuel supply port of an FVU unit, and the other end is connected with a fuel inlet of a main engine. A first annular space is formed between the inner wall of the first double-wall pipe and the outer wall of the first ammonia supply pipe, and the first annular space is connected with a ventilation inlet through a first ventilation pipe. A flow meter, a ventilation box, a flow switch, a throttle orifice plate, a first pressure gauge, and a second pressure gauge are sequentially arranged on the first ventilation pipe between the ventilation inlet and the first double-wall pipe. The ventilation box is connected with a compressed air system through a third ventilation pipe. The first ventilation pipe is connected with an ammonia adsorption device in an ammonia treatment and recovery system and a nitrogen supply system through a first nitrogen pipe. The second double-wall pipe is provided with a second ammonia supply pipe, one end of the second ammonia supply pipe is connected with an ammonia fuel return port of the FVU unit, and the other end is connected with a fuel outlet of the main machine; a second annular space is formed between an inner wall of the second double-wall pipe and an outer wall of the second ammonia supply pipe, and the second annular space is connected with a ventilation outlet through a second ventilation pipeline; An injector ventilation system, a three-way valve and an ammonia sensor are sequentially arranged on the second ventilation pipeline between the ventilation outlet and the second double-wall pipe, the three-way valve is connected with an ammonia adsorption device in an ammonia treatment and recovery system through a second ammonia recovery pipe, and the second ventilation pipeline is connected with a nitrogen supply system through a second nitrogen pipe; The ammonia leakage recovery port of the FVU unit is communicated with low points of the first annular space and the second annular space in the main machine through an ammonia leakage pipe; The main machine is internally provided with a plurality of sensors, which are an ammonia sensor, a pressure sensor, a liquid level sensor and a temperature sensor.

[0006] Preferably, a first check valve and a first pneumatic electromagnetic valve are arranged on the first ventilation pipeline between the first pressure gauge and the second pressure gauge; A second pneumatic electromagnetic valve and a second check valve are arranged on the second ventilation pipeline between the ventilation outlet and the injector ventilation system, a stop valve is arranged on the second ventilation pipeline between the injector ventilation system and the three-way valve, and an ammonia sensor and a third pneumatic electromagnetic valve are arranged on the second ventilation pipeline between the ammonia sensor and the second double-wall pipe; An adjustable orifice plate, a pressure regulating valve and a ninth pneumatic electromagnetic valve are sequentially arranged on the third ventilation pipeline.

[0007] Preferably, the nitrogen supply system includes a 3bar nitrogen supply system and a 30bar nitrogen supply system.

[0008] Preferably, one end of the first nitrogen pipe is connected with the first ventilation pipeline, located between the first pneumatic electromagnetic valve and the second pressure gauge of the first ventilation pipeline, the other end is divided into two paths, one path is connected with the ammonia adsorption device in the ammonia treatment and recovery system through a first ammonia recovery pipe, and the other path is divided into two branches, a first branch is connected with the 3bar nitrogen supply system through a first nitrogen branch pipe, and a second branch is connected with the 30bar nitrogen supply system through a second nitrogen branch pipe; A third check valve and a fourth pneumatic electromagnetic valve are arranged on the first nitrogen pipe close to one end of the first ventilation pipeline; a sixth pneumatic electromagnetic valve is arranged on the first nitrogen branch pipe, a seventh pneumatic electromagnetic valve is arranged on the second nitrogen branch pipe, and an eighth pneumatic electromagnetic valve is arranged on the first ammonia recovery pipe; One end of the second nitrogen pipe is connected with the second ventilation pipeline, located between the third pneumatic electromagnetic valve and the second double-wall pipe of the second ventilation pipeline, and the other end of the second nitrogen pipe is connected with the first nitrogen pipe and accesses the end close to the fourth pneumatic electromagnetic valve. A fourth check valve and a fifth pneumatic electromagnetic valve are arranged on the second nitrogen pipe close to one end of the second ventilation pipeline.

[0009] Preferably, the ejector ventilation system comprises an ejector, an ejector-driven water tank and a water pump, the ventilation inlet of the ejector is connected with the second double-wall pipe through the second ventilation pipeline, the ventilation outlet of the ejector is connected with the ventilation outlet through the second ventilation pipeline, the second ventilation pipeline is provided with an ammonia detector close to the ejector, the outflow end of the ejector, the ejector-driven water tank, the water pump and the inflow end of the ejector are connected in sequence through an internal water pipe to form a circulating water pipeline, the ejector-driven water tank is provided with an ammonia detector, and the ejector-driven water tank is externally connected with a medium cooling system for cooling the medium in the internal water pipe.

[0010] Preferably, the water pump in the ejector ventilation system generates power when running, so that high-pressure water in the internal water pipe forms a high-speed jet through the nozzle of the ejector, the high-speed jet forms a local low pressure at the ventilation outlet of the ejector, so that air is sucked into the second ventilation pipeline, and the air is continuously sucked into the second ventilation pipeline to generate an air extraction effect as the water pump continuously runs.

[0011] Preferably, one end of the ammonia leakage pipe is connected with the ammonia leakage recovery port of the FVU unit, the other end is divided into two paths, one path is connected with the first annular space through the first ammonia leakage branch pipe, and the other path is connected with the second annular space through the second ammonia leakage branch pipe. The first ammonia leakage branch pipe is provided with a tenth pneumatic electromagnetic valve, and the second ammonia leakage branch pipe is provided with an eleventh pneumatic electromagnetic valve; the first double-wall pipe is provided with a first stop valve at the connection position with the main machine, and the second double-wall pipe is provided with a second stop valve at the connection position with the main machine, and the first stop valve and the second stop valve are located in the main machine.

[0012] The present application has the following beneficial effects: The present application provides an ammonia fuel sealed double-wall pipe ventilation system, fully considers the risk caused by the self leakage of the fan, proposes a completely sealed ventilation scheme, and improves the safety of the whole ventilation system.

[0013] The application provides an ammonia fuel sealed double-wall pipe ventilation system, which considers the characteristic that ammonia is easily dissolved in water, can effectively perform preliminary adsorption when slight ammonia leakage occurs, and avoids forming a large toxic area and a dangerous area at a fan outlet. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a schematic diagram of the ammonia fuel sealed double-wall pipe ventilation system.

[0015] Figure 2 It is a schematic diagram of the ejector ventilation system.

[0016] In the figure, 1 is a main engine, 101 is a first double-wall pipe, 102 is a first ammonia supply pipe, 103 is a ventilation inlet, 104 is a flow meter, 105 is a ventilation box, 106 is a flow switch, 107 is a throttle orifice plate, 108 is a first pressure gauge, 109 is a first check valve, 110 is a first pneumatic electromagnetic valve, 111 is a second pressure gauge, 201 is a second double-wall pipe, 202 is a second ammonia supply pipe, 203 is a ventilation outlet, 204 is a second pneumatic electromagnetic valve, 205 is a second check valve, 206 is a stop valve, 207 is a three-way valve, 208 is an ammonia sensor, 209 is a third pneumatic electromagnetic valve, 3 is a third ventilation pipeline, 301 is an adjustable flow orifice plate, 302 is a pressure regulating valve, 303 is a ninth pneumatic electromagnetic valve, 4 is an FVU unit, 401 is an ammonia fuel supply port, 402 is an ammonia fuel return port, 403 is an ammonia leakage recovery port, 5 is a compressed air system, 6 is a nitrogen supply system, 601 is a 3 bar nitrogen supply system, 602 is a 30 bar nitrogen supply system, 603 is a third check valve, 604 is a fourth pneumatic electromagnetic valve, 605 is a sixth pneumatic electromagnetic valve, 606 is a seventh pneumatic electromagnetic valve, 607 is an eighth pneumatic electromagnetic valve, 608 is a fourth check valve, 609 is a fifth pneumatic electromagnetic valve, 7 is an ammonia adsorption device, 8 is an ejector ventilation system, 801 is an ejector, 802 is an ejector drive water tank, 803 is a water pump, and 804 is an ammonia detector. DETAILED DESCRIPTION

[0017] The application provides an ammonia fuel sealed double-wall pipe ventilation system, for the purpose, technical scheme and effect of the application are more clear and definite, the application is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the application, and are not used to limit the application.

[0018] The application will be described in detail below with reference to the accompanying drawings: The embodiment proposes an ammonia fuel sealed double-wall pipe ventilation system, as shown in the accompanying drawings, comprising a first double-wall pipe 101, a second double-wall pipe 201, a ventilation tank, and an ejector ventilation system. Figure 1

[0019] The first double-wall pipe 101 is provided with a first ammonia supply pipe 102, one end of which is connected to an ammonia fuel supply port 401 of an FVU unit 4 (i.e. an ammonia fuel valve group unit), and the other end is connected to a fuel inlet of a host machine 1; a first annular space is formed between the inner wall of the first double-wall pipe and the outer wall of the first ammonia supply pipe, and the first annular space is connected to a ventilation inlet through a first ventilation pipe.

[0020] The second double-wall pipe 201 is provided with a second ammonia supply pipe 202, one end of which is connected to an ammonia fuel return port 402 of the FVU unit 4, and the other end is connected to a fuel outlet of the host machine; a second annular space is formed between the inner wall of the second double-wall pipe and the outer wall of the second ammonia supply pipe, and the second annular space is connected to a ventilation outlet through a second ventilation pipe.

[0021] Further, the first ventilation pipe between the ventilation inlet 103 and the first double-wall pipe 101 is provided with a flow meter 104, a ventilation tank 105, a flow switch 106, an orifice plate 107, a first pressure gauge 108, a first check valve 109, a first pneumatic electromagnetic valve 110, and a second pressure gauge 11 in sequence, and the ventilation tank is connected to a compressed air system 5 through a third ventilation pipe; the first ventilation pipe is connected to a nitrogen supply system 6 and an ammonia adsorption device in an ammonia treatment and recovery system through a first nitrogen pipe.

[0022] The second ventilation pipe between the ventilation outlet 203 and the second double-wall pipe is provided with a second pneumatic electromagnetic valve 204, a second check valve 205, an ejector ventilation system 8, a stop valve 206, a three-way valve 207, an ammonia sensor 208, and a third pneumatic electromagnetic valve 209 in sequence.

[0023] The third ventilation pipe is provided with an adjustable orifice plate 301, a pressure regulating valve 302, and a ninth pneumatic electromagnetic valve 303 in sequence.

[0024] The host machine is provided with a plurality of sensors, including an ammonia sensor, a pressure sensor, a liquid level sensor, and a temperature sensor.

[0025] Further, an ammonia leakage recovery port 403 of the FVU unit 4 is connected to the low points of the first annular space and the second annular space in the host machine through an ammonia leakage pipe.

[0026] ​The ammonia leakage pipe is connected with the ammonia leakage recovery port of the FVU unit at one end, and is divided into two routes at the other end, one of which is connected with the low point of the first annular space through the first ammonia leakage branch pipe, and the other of which is connected with the low point of the second annular space through the second ammonia leakage branch pipe.

[0027] The tenth pneumatic electromagnetic valve is arranged on the first ammonia leakage branch pipe, and the eleventh pneumatic electromagnetic valve is arranged on the second ammonia leakage branch pipe; the first stop valve is arranged at the connection position of the first double-wall pipe and the main machine, the second stop valve is arranged at the connection position of the second double-wall pipe and the main machine, and the first stop valve and the second stop valve are located in the main machine.

[0028] Further, the nitrogen supply system 6 includes a 3 bar nitrogen supply system 601 and a 30 bar nitrogen supply system 602, which are respectively used to provide nitrogen with a pressure of 3 bar and nitrogen with a pressure of 30 bar.

[0029] One end of the first nitrogen pipe is connected with the first ventilation pipeline, is located between the first pneumatic electromagnetic valve ASV03 and the second pressure gauge ASF07 in the first ventilation pipeline, and the other end is divided into two routes, one of which is connected with the ammonia adsorption device in the ammonia treatment and recovery system through the first ammonia recovery pipe, and the other of which is divided into two branch pipes, one of which is connected with the 3 bar nitrogen supply system through the first nitrogen branch pipe, and the other of which is connected with the 30 bar nitrogen supply system through the second nitrogen branch pipe.

[0030] The third check valve 603 and the fourth pneumatic electromagnetic valve 604 are arranged on the first nitrogen pipe close to one end of the first ventilation pipeline; the sixth pneumatic electromagnetic valve 605 is arranged on the first nitrogen branch pipe, and the seventh pneumatic electromagnetic valve 606 is arranged on the second nitrogen branch pipe; and the eighth pneumatic electromagnetic valve 607 is arranged on the first ammonia recovery pipe.

[0031] One end of the second nitrogen pipe is connected with the second ventilation pipeline, is located between the third pneumatic electromagnetic valve and the second double-wall pipe in the second ventilation pipeline, and the other end of the second nitrogen pipe is connected with the first nitrogen pipe and is connected close to the fourth pneumatic electromagnetic valve 604; the fourth check valve 608 and the fifth pneumatic electromagnetic valve 609 are arranged on the second nitrogen pipe close to one end of the second ventilation pipeline.

[0032] Further, the ejector ventilation system 8 in the embodiment is as shown in FIG. 6. Figure 2As shown, the ejector 801, the ejector driving water tank 802 and the water pump 803 are connected in series through the internal water pipe to form a circulating water circuit, the ventilation inlet of the ejector is connected with the second double-wall pipe through the second ventilation pipe, the ventilation outlet of the ejector is connected with the ventilation outlet through the second ventilation pipe, the outflow end of the ejector, the ejector driving water tank, the water pump and the inflow end of the ejector are connected in series through the internal water pipe to form a circulating water circuit, the ammonia detector 804 is arranged on the ejector driving water tank and the side of the second ventilation pipe close to the ejector, and the medium cooling system is connected with the ejector driving water tank, and is used for cooling the medium in the internal water pipe.

[0033] Specifically, the operation principle of the ejector ventilation system in the embodiment is as follows: In the ejector ventilation system, the ejector 801, the ejector driving water tank 802 and the water pump 803 are connected in series through the internal water pipe to form a circulating water circuit, the water pump is operated to generate power, so that the high-pressure water with a pressure of about 1.0 MPa in the internal water pipe forms a high-speed jet through the nozzle of the ejector, the high-speed jet forms a local low pressure at the ventilation outlet of the ejector, so that air is sucked into the second ventilation pipe, and the air is continuously sucked into the second ventilation pipe to generate the air extraction effect with the continuous operation of the water pump.

[0034] Regarding the selection of the water pump and the ejector in the ejector ventilation system, the type of the water pump and the ejector in the ejector ventilation system is selected according to the required ventilation volume and static pressure of the ventilation pipe, and the water pump and the ejector are selected according to the displacement and pressure of the driving water.

[0035] Normally, there is no ammonia in the circulating water circuit in the ejector ventilation system, if a small amount of ammonia is mixed into the ejector driving water tank during long-time operation, the ammonia detector arranged on the ejector driving water tank can detect the presence of ammonia water in the circulating water circuit, and measure the ammonia water concentration in the circulating water circuit, when the ammonia water concentration in the circulating water circuit reaches 10 ppm, an alarm will be given to remind the system to perform water replacement treatment.

[0036] At the same time, due to the increase of the temperature of the circulating water in the circulating water circuit of the ejector ventilation system during long-time operation, a water glycol cooling system is arranged in the embodiment to cool the circulating water in the circulating water circuit by using water glycol to reduce the temperature of the circulating water.

[0037] Specifically, the operation principle of the ammonia fuel sealed double-wall pipe ventilation system in the embodiment is as follows: When the main engine is operated under the ammonia model, the ammonia fuel sealed double-wall pipe ventilation system is normally operated, the ventilation volume is 30 times / hour, the ventilation flow direction is that the air is introduced through the ventilation inlet or the pressure regulating valve of the compressed air system, enters the ejector ventilation system through the three-way valve of the second ventilation pipe, is discharged to the ventilation outlet 16 m away from the main deck through the ejector ventilation system, and is discharged through the ventilation outlet.

[0038] Because the ammonia fuel sealed double-wall pipe ventilation system in the embodiment is provided with two air inlets, when the air outside the cabin is dry, the air inlets can suck air from outside the cabin, and when the air outside the cabin is humid, the air inlets can suck dry compressed air from inside the cabin.

[0039] Open the related valves on the first ventilation pipeline and the second ventilation pipeline, close the ninth pneumatic electromagnetic valve on the third ventilation pipeline, open the fan, measure the outlet air speed of the ejector ventilation system, calculate the ventilation volume according to the air speed, and adjust the size of the orifice plate according to the measured data of the flowmeter so that the ventilation volume is 30 times per minute. After the ventilation volume is adjusted, open the compressed air inlet valve, i.e. the ninth pneumatic electromagnetic valve on the third ventilation pipeline, and adjust the size of the orifice plate so that there is a small amount of ventilation overflow at the original outdoor ventilation inlet, which can also be seen from the flow direction of the flowmeter; check the flow switch at the outlet of the ventilation box, which is used to detect the state of the ventilation system.

[0040] Considering that ammonia leakage may occur during the operation of the main engine in ammonia mode or during the purging process, in order to monitor the ammonia leakage, various types of sensors are provided in the ammonia fuel sealed double-wall pipe ventilation system to detect ammonia leakage. At the same time, in order to detect ammonia vaporization, an ammonia sensor is also provided on the second ventilation pipeline to monitor any possible ammonia leakage that may vaporize into the annular space.

[0041] For the treatment of small ammonia leakage, when small ammonia leakage occurs, the liquid level sensor will not trigger an alarm, and at this time only the ammonia sensor provided on the second ventilation pipeline can identify the slight ammonia vapor leakage. When ammonia gas leakage is detected, the ammonia fuel sealed double-wall pipe ventilation system will dilute the ammonia gas until it reaches a safe concentration for discharge, at which time the main engine switches to diesel mode, the ammonia supply system stops supplying, and the system is purged.

[0042] For the treatment of large ammonia leakage, when large amounts of ammonia gas leak, the leakage is so large that the ammonia will not vaporize quickly, at which time the annular space is filled with liquid ammonia, and the liquid level sensor provided inside the main engine detects the liquid ammonia leakage, and once the liquid level sensor detects the liquid ammonia leakage, it will automatically trigger a purge, first using 30 bar nitrogen to purge the ammonia supply pipe, then using 30 bar nitrogen to purge the annular space, and then using 3 bar nitrogen to purge the annular space, and then performing negative pressure exhaust on the annular space.

[0043] Specifically, for the purging of the ammonia supply pipe (i.e. the inner pipe), once the liquid level sensor detects ammonia leakage, the ammonia supply is immediately stopped, and at the same time the emergency purge is started, using 30 bar nitrogen to purge the ammonia supply pipe. During the purging process, the nitrogen will purge the liquid ammonia in the ammonia supply pipe to the annular space, until the purging of the ammonia supply pipe is stopped when the leakage is over, and the purging of the annular space inside the double-wall pipe continues.

[0044] For the annular space purging, access 30bar nitrogen, close the first pneumatic solenoid valve and the third pneumatic solenoid valve, nitrogen will the liquid ammonia in the upper end of the annular space purged to the two lowest points of the tenth pneumatic solenoid valve and the eleventh pneumatic solenoid valve, purged to the ammonia leakage outlet of the FVU unit, then through the DBB valve on the FVU unit back to the water tank of the ammonia head cooling unit, after completing the upper end pipeline purging of the annular space, the next operation will be performed.

[0045] Close the nitrogen pipe in the air inlet pipeline, through the 30bar nitrogen in the air outlet pipe, through the tenth pneumatic solenoid valve to purge the liquid ammonia in the annular space to the water tank, after purging, close the tenth pneumatic solenoid valve.

[0046] Repeat the liquid ammonia from the inner tube, in the previous step of purging the annular space, some ammonia can be blown back to the inner tube, therefore, it is necessary to purge the inner tube again, the liquid ammonia in the inner tube is blown back to the ammonia collection pipe.

[0047] After performing the above steps, the residual amount of leakage is very small, and can be volatilized.

[0048] After purging the inner tube and the annular space, ammonia gas purging is performed on the inner tube and the annular space, using 3bar nitrogen to purge the residual ammonia in the annular space to the ammonia treatment and recovery system through the ventilation inlet, when the ammonia sensor monitors that the ammonia concentration meets the standard, the three-way valve can be turned to the ejector ventilation system side, the nitrogen supply is closed, the air inlet is opened, the ventilation system is started, and the annular space is ventilated.

[0049] Of course, the above description is not a limitation of the present application, the present application is not limited to the above examples, the changes, modifications, additions or replacements made by the person skilled in the art within the essential scope of the present application should also belong to the protection scope of the present application.

Claims

1. An ammonia fuel-sealed double-walled pipe ventilation system, characterized in that, Includes a first double-walled pipe, a second double-walled pipe, a ventilation box, and an ejector ventilation system; The first double-walled tube is provided with a first ammonia supply pipe. One end of the first ammonia supply pipe is connected to the ammonia fuel supply port of the FVU unit, and the other end is connected to the fuel inlet of the main unit. A first annular space is formed between the inner wall of the first double-walled tube and the outer wall of the first ammonia supply pipe. The first annular space is connected to the ventilation inlet through a first ventilation pipe. A flow meter, a ventilation box, a flow switch, a throttling orifice plate, a first pressure gauge, and a second pressure gauge are sequentially installed on the first ventilation duct between the ventilation inlet and the first double-walled pipe. The ventilation box is connected to the compressed air system through a third ventilation duct. The first ventilation duct is connected to the nitrogen supply system and the ammonia adsorption device in the ammonia treatment and recovery system through a first nitrogen pipe. The second double-walled tube is provided with a second ammonia supply pipe. One end of the second ammonia supply pipe is connected to the ammonia fuel return port of the FVU unit, and the other end is connected to the fuel outlet of the main unit. A second annular space is formed between the inner wall of the second double-walled tube and the outer wall of the second ammonia supply pipe. The second annular space is connected to the ventilation outlet through a second ventilation pipe. The second ventilation duct between the ventilation outlet and the second double-walled pipe is sequentially equipped with an ejector ventilation system, a three-way valve and an ammonia sensor. The three-way valve is connected to the ammonia adsorption device in the ammonia treatment and recovery system through the second ammonia recovery pipe. The second ventilation duct is connected to the nitrogen supply system through the second nitrogen pipe. The ammonia leakage recovery port of the FVU unit is connected to the lowest point of the first annular space and the second annular space in the main unit through an ammonia leakage pipe. The host is equipped with multiple sensors, namely an ammonia sensor, a pressure sensor, a liquid level sensor, and a temperature sensor.

2. The ammonia fuel sealed double-walled pipe ventilation system according to claim 1, characterized in that, A first check valve and a first pneumatic solenoid valve are installed on the first ventilation pipe between the first pressure gauge and the second pressure gauge. A second pneumatic solenoid valve and a second check valve are installed on the second ventilation duct between the ventilation outlet and the injector ventilation system. A shut-off valve is installed on the second ventilation duct between the injector ventilation system and the three-way valve. An ammonia sensor and a third pneumatic solenoid valve are installed on the second ventilation duct between the ammonia sensor and the second double-walled pipe. The third ventilation duct is sequentially equipped with an adjustable flow orifice plate, a pressure regulating valve, and a ninth pneumatic solenoid valve.

3. The ammonia fuel sealed double-walled pipe ventilation system according to claim 2, characterized in that, The nitrogen supply system includes a 3-bar nitrogen supply system and a 30-bar nitrogen supply system.

4. The ammonia fuel sealed double-walled pipe ventilation system according to claim 3, characterized in that, One end of the first nitrogen pipe is connected to the first ventilation pipe and is located between the first pneumatic solenoid valve and the second pressure gauge in the first ventilation pipe. The other end is divided into two paths. One path is connected to the ammonia adsorption device in the ammonia treatment and recovery system through the first ammonia recovery pipe. The other path is divided into two branches. The first branch is connected to the 3 bar nitrogen supply system through the first nitrogen branch pipe, and the second branch is connected to the 30 bar nitrogen supply system through the second nitrogen branch pipe. A third check valve and a fourth pneumatic solenoid valve are installed on the first nitrogen pipe near the first ventilation pipe; a sixth pneumatic solenoid valve is installed on the first nitrogen branch pipe; a seventh pneumatic solenoid valve is installed on the second nitrogen branch pipe; and an eighth pneumatic solenoid valve is installed on the first ammonia recovery pipe. One end of the second nitrogen pipe is connected to the second ventilation duct and is located between the third pneumatic solenoid valve and the second double-walled pipe of the second ventilation duct. The other end of the second nitrogen pipe is connected to the first nitrogen pipe and the access end is close to the fourth pneumatic solenoid valve. A fourth check valve and a fifth pneumatic solenoid valve are installed on the second nitrogen pipe near the second ventilation pipe.

5. The ammonia fuel sealed double-walled pipe ventilation system according to claim 1, characterized in that, The injector ventilation system includes an injector, an injector drive water tank, and a water pump. The ventilation inlet of the injector is connected to a second double-walled pipe through a second ventilation duct, and the ventilation outlet of the injector is connected to a ventilation outlet through a second ventilation duct. An ammonia detector is installed on the side of the second ventilation duct near the injector. The outlet end of the injector, the injector drive water tank, the water pump, and the inlet end of the injector are sequentially connected through internal water pipes to form a circulating water circuit. An ammonia detector is installed on the injector drive water tank, and a medium cooling system is connected to the outside of the injector drive water tank to cool the medium in the internal water pipes.

6. The ammonia fuel sealed double-walled pipe ventilation system according to claim 5, characterized in that, The pump in the ejector ventilation system generates power during operation, causing high-pressure water in the internal water pipe to form a high-speed jet through the nozzle of the ejector. The high-speed jet creates a local low pressure at the ventilation outlet of the ejector, thereby drawing air into the second ventilation duct. As the pump continues to operate, air is continuously drawn into the second ventilation duct, producing a ventilation effect.

7. The ammonia fuel sealed double-walled pipe ventilation system according to claim 1, characterized in that, One end of the ammonia leak pipe is connected to the ammonia leak recovery port of the FVU unit, and the other end is divided into two paths: one path is connected to the first annular space through the first ammonia leak branch pipe, and the other path is connected to the second annular space through the second ammonia leak branch pipe. A tenth pneumatic solenoid valve is installed on the first ammonia leakage branch pipe, and an eleventh pneumatic solenoid valve is installed on the second ammonia leakage branch pipe; a first shut-off valve is installed at the connection between the first double-walled pipe and the main unit, and a second shut-off valve is installed at the connection between the second double-walled pipe and the main unit, both of which are located inside the main unit.

Images